This invention relates in general to the location of the pivot point on a steering knuckle mechanism and in particular to altering the pivot point location of the steering arm portion of the knuckle to the tie rod connection, in order to alter a non adjustable steering alignment angle.
The location of the steering arm pivot point in relation to the pivot axis of the front wheel, is a primary detriment in establishing what is known as the Ackerman Angle, and in creating a necessary steering alignment condition known as toe-out in turns. This invention does not intend to quantify the specific requirements of toe-out in turns for a particular vehicle configuration, nor does it intend to teach how the preferred settings at low speed are altered at higher speeds under the influence of varying inside to outside tire slip angles. This tire slip condition is created by centrifugal force acting on the vehicle center of gravity at higher vehicle speeds. The invention simply provides a device which will allow this parameter to be altered from factory specifications in order to accommodate vehicle demands which can vary from one set of operating conditions to another.
In most automobiles the rear wheels travel in a straight forward direction and the forward wheels are turned in order to make the vehicle change direction. It's desirable that all the wheels in a vehicle track about a common turning center in order to minimize tire wear. This turning center (at low speed) is located on a line extending from the rear axle and the intersection of lines drawn through the axis of each front wheel. The inside front wheel must travel around a circle which has a smaller radius than the circle the outside front wheel travels around. Thus, the inside wheel should have a greater turn angle than the outside wheel. These angles are established to a large extent by location of the pivot point for the steering arm in relation to the steering axis for the wheel. Each steering arm rotates through its own arc of travel. It rotates on its axis when the front wheels are turned. The angle of these arms in relation to the wheel steering axis causes one wheel to turn more sharply than the other.
If the angle of the outside wheel is too great in relation to the inside wheel in a turn the front tires will scrub along the outer edge causing excessive tire wear. This problem may be corrected by altering the location of the pivot point of the steering mechanism. However, this pivot point is established during design of a particular vehicle and is not adjustable after the automobile has been manufactured.
One means for moving the steering arm pivot point on existing vehicles is to relocate the appropriate pivot points on the steering knuckle. Steering knuckles, however, are usually good for the life of the vehicle and are not normally replaced. Also steering knuckles are expensive parts and this would not be an economic solution.